// File: examples/mock_server.rs

//! Comprehensive Mock KRA eTims server for local development
//! 
//! Run with: cargo run --example mock_server
//! Then set DEV_API_BASE_URL=http://127.0.0.1:8888 in your .env

use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpListener;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("╔════════════════════════════════════════════════════════════════╗");
    println!("║       Mock KRA eTIMS Server (Development Only)                 ║");
    println!("╠════════════════════════════════════════════════════════════════╣");
    println!("║  Company: ITERATE IOT LIMITED (P052038091H)                    ║");
    println!("║  Listening on: http://127.0.0.1:8888                           ║");
    println!("║                                                                ║");
    println!("║  Set in .env:                                                  ║");
    println!("║    DEV_API_BASE_URL=http://127.0.0.1:8888                       ║");
    println!("║    API_USERNAME=test_user                                      ║");
    println!("║    API_PASSWORD=test_pass                                      ║");
    println!("╚════════════════════════════════════════════════════════════════╝");
    println!();

    let listener = TcpListener::bind("127.0.0.1:8888").await?;
    println!("🚀 Mock server started. Waiting for requests...\n");

    loop {
        let (mut socket, addr) = listener.accept().await?;

        tokio::spawn(async move {
            let mut buf = vec![0u8; 8192];

            match socket.read(&mut buf).await {
                Ok(n) if n > 0 => {
                    let request = String::from_utf8_lossy(&buf[..n]);
                    let first_line = request.lines().next().unwrap_or("");
                    
                    println!("📥 [{}] {}", addr, first_line);

                    let (status, body) = route_request(&request);
                    
                    let response = format!(
                        "HTTP/1.1 {}\r\n\
                         Content-Type: application/json\r\n\
                         Content-Length: {}\r\n\
                         Access-Control-Allow-Origin: *\r\n\
                         Access-Control-Allow-Methods: GET, POST, OPTIONS\r\n\
                         Access-Control-Allow-Headers: Content-Type, Authorization\r\n\
                         Connection: close\r\n\
                         \r\n\
                         {}",
                        status,
                        body.len(),
                        body
                    );

                    let _ = socket.write_all(response.as_bytes()).await;
                    
                    let preview = if body.len() > 80 { 
                        format!("{}...", &body[..80]) 
                    } else { 
                        body.clone() 
                    };
                    println!("📤 [{}] {} - {}", addr, status, preview);
                }
                _ => {}
            }
        });
    }
}

fn route_request(request: &str) -> (&'static str, String) {
    let path = request
        .lines()
        .next()
        .and_then(|line| line.split_whitespace().nth(1))
        .unwrap_or("");

    // Handle OPTIONS preflight
    if request.starts_with("OPTIONS") {
        return ("204 No Content", String::new());
    }

    match path {
        p if p.contains("/oauth2/v1/generate") => {
            ("200 OK", mock_token_response())
        }
        p if p.contains("/selectInitOsdcInfo") => {
            ("200 OK", mock_init_osdc_response())
        }
        p if p.contains("/selectCodeList") => {
            ("200 OK", mock_code_list_response())
        }
        p if p.contains("/selectItemClsList") => {
            ("200 OK", mock_item_cls_response())
        }
        p if p.contains("/selectBhfList") => {
            ("200 OK", mock_bhf_list_response())
        }
        p if p.contains("/sendSalesTrns") => {
            ("200 OK", mock_send_sales_response())
        }
        p if p.contains("/selectSalesTrns") => {
            ("200 OK", mock_select_sales_response())
        }
        p if p.contains("/selectNoticeList") => {
            ("200 OK", mock_notice_response())
        }
        p if p.contains("/selectTaxpayerInfo") => {
            ("200 OK", mock_taxpayer_response())
        }
        p if p.contains("/selectCustomerList") => {
            ("200 OK", mock_customer_response())
        }
        p if p.contains("/selectMoveList") => {
            ("200 OK", mock_move_list_response())
        }
        p if p.contains("/saveStockMaster") => {
            ("200 OK", mock_save_stock_response())
        }
        p if p.contains("/selectPurchaseTrns") => {
            ("200 OK", mock_purchase_response())
        }
        p if p.contains("/saveItem") => {
            ("200 OK", mock_save_item_response())
        }
        p if p.contains("/selectImportItemList") => {
            ("200 OK", mock_import_items_response())
        }
        _ => {
            println!("⚠️  Unknown endpoint: {}", path);
            ("404 Not Found", format!(
                r#"{{"resultCd": "9999", "resultMsg": "Endpoint not found: {}"}}"#, 
                path
            ))
        }
    }
}

fn mock_token_response() -> String {
    r#"{
    "access_token": "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.mock_token_for_iterate_iot",
    "token_type": "Bearer",
    "expires_in": 3600,
    "scope": "read write"
}"#.to_string()
}

fn mock_init_osdc_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "tin": "P052038091H",
        "bhfId": "00",
        "dvcSrlNo": "ITERATE-DEV-001",
        "sdcId": "SDC-ITERATE-001",
        "mrcNo": "MRC-001",
        "lastSaleInvcNo": 0,
        "lastPchsInvcNo": 0,
        "lastSaleRcptNo": 0,
        "lastInvcNo": 0,
        "lastTrainInvcNo": 0,
        "lastProfrmInvcNo": 0,
        "lastCopyInvcNo": 0
    }
}"#.to_string()
}

fn mock_code_list_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "clsList": [
            {"cdCls": "01", "cdClsNm": "Tax Type", "cdClsDesc": "Tax Type Codes"},
            {"cdCls": "02", "cdClsNm": "Country", "cdClsDesc": "Country Codes"},
            {"cdCls": "03", "cdClsNm": "Quantity Unit", "cdClsDesc": "Quantity Unit Codes"},
            {"cdCls": "04", "cdClsNm": "Package Unit", "cdClsDesc": "Package Unit Codes"},
            {"cdCls": "05", "cdClsNm": "Payment Type", "cdClsDesc": "Payment Type Codes"}
        ],
        "dtlList": [
            {"cdCls": "01", "cd": "A", "cdNm": "A-EX", "cdDesc": "Exempt"},
            {"cdCls": "01", "cd": "B", "cdNm": "B-16.00%", "cdDesc": "Standard Rate 16%"},
            {"cdCls": "01", "cd": "C", "cdNm": "C-0%", "cdDesc": "Zero Rated"},
            {"cdCls": "01", "cd": "D", "cdNm": "D-Non-VAT", "cdDesc": "Non-VAT"},
            {"cdCls": "01", "cd": "E", "cdNm": "E-8%", "cdDesc": "8% VAT"},
            {"cdCls": "02", "cd": "KE", "cdNm": "Kenya", "cdDesc": "Republic of Kenya"},
            {"cdCls": "03", "cd": "EA", "cdNm": "Each", "cdDesc": "Each/Piece"},
            {"cdCls": "03", "cd": "KG", "cdNm": "Kilogram", "cdDesc": "Kilogram"},
            {"cdCls": "03", "cd": "LT", "cdNm": "Litre", "cdDesc": "Litre"},
            {"cdCls": "04", "cd": "BX", "cdNm": "Box", "cdDesc": "Box"},
            {"cdCls": "04", "cd": "CT", "cdNm": "Carton", "cdDesc": "Carton"},
            {"cdCls": "05", "cd": "01", "cdNm": "Cash", "cdDesc": "Cash Payment"},
            {"cdCls": "05", "cd": "02", "cdNm": "Credit", "cdDesc": "Credit Payment"},
            {"cdCls": "05", "cd": "03", "cdNm": "Mobile", "cdDesc": "Mobile Money"}
        ]
    }
}"#.to_string()
}

fn mock_item_cls_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "itemClsList": [
            {"itemClsCd": "KE1NTXU000", "itemClsNm": "General Goods", "itemClsLvl": 1, "taxTyCd": "B", "mjrTgYn": "N", "useYn": "Y"},
            {"itemClsCd": "KE2NTXU001", "itemClsNm": "Electronics", "itemClsLvl": 2, "taxTyCd": "B", "mjrTgYn": "N", "useYn": "Y"},
            {"itemClsCd": "KE2NTXU002", "itemClsNm": "Food & Beverages", "itemClsLvl": 2, "taxTyCd": "A", "mjrTgYn": "N", "useYn": "Y"},
            {"itemClsCd": "KE2NTXU003", "itemClsNm": "IoT Devices", "itemClsLvl": 2, "taxTyCd": "B", "mjrTgYn": "N", "useYn": "Y"},
            {"itemClsCd": "KE2NTXU004", "itemClsNm": "Software & Services", "itemClsLvl": 2, "taxTyCd": "B", "mjrTgYn": "N", "useYn": "Y"}
        ]
    }
}"#.to_string()
}

fn mock_bhf_list_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "bhfList": [
            {
                "tin": "P052038091H",
                "bhfId": "00",
                "bhfNm": "ITERATE IOT LIMITED - Head Office",
                "bhfSttsCd": "A",
                "prvncNm": "Nairobi",
                "dstrtNm": "Westlands",
                "sctrNm": "Parklands",
                "locDesc": "Innovation Hub, 4th Floor",
                "mgrNm": "Manager",
                "mgrTelNo": "+254700000000",
                "mgrEmail": "info@iterateiot.com"
            }
        ]
    }
}"#.to_string()
}

fn mock_send_sales_response() -> String {
    use std::time::{SystemTime, UNIX_EPOCH};
    let timestamp = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap()
        .as_secs();
    
    format!(r#"{{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {{
        "rcptNo": {},
        "intrlData": "MOCK-INTERNAL-DATA-{}",
        "rcptSign": "MOCK-SIGNATURE-{}",
        "sdcDateTime": "20240207120000",
        "sdcId": "SDC-ITERATE-001",
        "mrcNo": "MRC-001",
        "qrCodeUrl": "https://etims.kra.go.ke/verify?code=MOCK{}",
        "totTaxAmt": 160.00,
        "totAmt": 1160.00
    }}
}}"#, timestamp % 10000, timestamp, timestamp, timestamp)
}

fn mock_select_sales_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "salesList": [
            {
                "invcNo": "INV-2024-0001",
                "salesDt": "20240207",
                "custTin": "A012345678X",
                "custNm": "Test Customer",
                "totItemCnt": 2,
                "totTaxblAmt": 1000.00,
                "totTaxAmt": 160.00,
                "totAmt": 1160.00,
                "rcptTyCd": "S",
                "salesSttsCd": "02"
            },
            {
                "invcNo": "INV-2024-0002",
                "salesDt": "20240207",
                "custTin": "P987654321Y",
                "custNm": "Another Customer",
                "totItemCnt": 1,
                "totTaxblAmt": 500.00,
                "totTaxAmt": 80.00,
                "totAmt": 580.00,
                "rcptTyCd": "S",
                "salesSttsCd": "02"
            }
        ]
    }
}"#.to_string()
}

fn mock_notice_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "noticeList": [
            {
                "noticeNo": "N-2024-001",
                "title": "eTIMS System Update",
                "cont": "The eTIMS system will undergo scheduled maintenance on Sunday.",
                "regDt": "20240201",
                "dtlUrl": "https://etims.kra.go.ke/notices/001"
            },
            {
                "noticeNo": "N-2024-002",
                "title": "New VAT Rates Effective",
                "cont": "Please note the updated VAT rates effective from the new fiscal year.",
                "regDt": "20240115",
                "dtlUrl": "https://etims.kra.go.ke/notices/002"
            }
        ]
    }
}"#.to_string()
}

fn mock_taxpayer_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "tin": "P052038091H",
        "taxprNm": "ITERATE IOT LIMITED",
        "taxprSttsCd": "A",
        "taxprSttsNm": "Active",
        "prvncNm": "Nairobi",
        "dstrtNm": "Westlands",
        "sctrNm": "Parklands",
        "locDesc": "Innovation Hub, 4th Floor",
        "isVatReg": "Y",
        "vatRegDt": "20230101"
    }
}"#.to_string()
}

fn mock_customer_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "custList": [
            {
                "custNo": "CUST-001",
                "custTin": "A012345678X",
                "custNm": "John Doe",
                "adrs": "123 Main Street, Nairobi",
                "telNo": "+254700111222",
                "email": "john.doe@example.com",
                "useYn": "Y"
            },
            {
                "custNo": "CUST-002",
                "custTin": "P987654321Y",
                "custNm": "ABC Company Ltd",
                "adrs": "456 Business Park, Mombasa",
                "telNo": "+254700333444",
                "email": "info@abccompany.co.ke",
                "useYn": "Y"
            }
        ]
    }
}"#.to_string()
}

fn mock_move_list_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "stockList": [
            {
                "itemCd": "ITEM-001",
                "itemNm": "IoT Sensor Module",
                "rsdQty": 150.0,
                "pkgUnitCd": "EA",
                "lastMvDt": "20240206"
            },
            {
                "itemCd": "ITEM-002",
                "itemNm": "WiFi Gateway",
                "rsdQty": 50.0,
                "pkgUnitCd": "EA",
                "lastMvDt": "20240205"
            }
        ]
    }
}"#.to_string()
}

fn mock_save_stock_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "itemCd": "ITEM-NEW-001",
        "regrId": "SYSTEM",
        "regrNm": "System"
    }
}"#.to_string()
}

fn mock_purchase_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "purchaseList": [
            {
                "invcNo": "PUR-2024-001",
                "spplrTin": "P111222333Z",
                "spplrNm": "Supplier Company",
                "pchsDt": "20240201",
                "totItemCnt": 5,
                "totTaxblAmt": 50000.00,
                "totTaxAmt": 8000.00,
                "totAmt": 58000.00
            }
        ]
    }
}"#.to_string()
}

fn mock_save_item_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "itemCd": "ITEM-NEW-001"
    }
}"#.to_string()
}

fn mock_import_items_response() -> String {
    r#"{
    "resultCd": "0000",
    "resultMsg": "Successful",
    "resultDt": "20240207120000",
    "data": {
        "itemList": []
    }
}"#.to_string()
}